why are all the planets in an almost round shape?

[kirti_astronomer]

i would like to know the answer

 

[pyoko]

They don't know the whole process of how planets form, but once they gather enough material, they collapse from gravity. It's easy to see why they would collapse to form a sphere. link<br /><br /> <div class="Discussion_UserSignature"> <p> </p><p> </p><p><span style="color:#ff9900" class="Apple-style-span">-pyoko</span> <span style="color:#333333" class="Apple-style-span">the</span> <span style="color:#339966" class="Apple-style-span">duck </span></p><p><span style="color:#339966" class="Apple-style-span"><span style="color:#808080;font-style:italic" class="Apple-style-span">It is by will alone I set my mind in motion.</span></span></p> </div>

 

[alokmohan]

This is very interesting I dont know the reply.

 

[MeteorWayne]

Early in their lives, planets become molten. Since it is a liquid, the shape with the least potential energy is a sphere, just like a raindrop. SO planets that melt assume that shape. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[nexium]

Even if the temperature did not warm to zero c = 32 f, a cube shaped planet with the mass of Mars or more, would quickly crush the hardest rock, until it was approximately spherical. Neil

 

[MeteorWayne]

Good point, Neil. <br /><br />But become liquid water or rock makes it easier <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[alokmohan]

nexium you are apparently right

 

[enigma10]

melting planets scare me. <img src="/images/icons/tongue.gif" /> <div class="Discussion_UserSignature"> <em>"<font color="#333399">An organism at war with itself is a doomed organism." - Carl Sagan</font></em> </div>

 

[bdewoody]

Isn't it something about conservation of energy? In space the least energetic grouping of matter will result in a sphere. <div class="Discussion_UserSignature"> <em><font size="2">Bob DeWoody</font></em> </div>

 

[derekmcd]

Any object will always 'pull' everything as close as possible towards its center of mass. Given enough mass to overcome the strength of the material, the natural outcome is a sphere. The larger the object, the less deviations from a perfect sphere it will have. This is why Mars can maintain mountains much larger that what earth can support. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[why06]

<blockquote><font class="small">In reply to:</font><hr /><p>Any object will always 'pull' everything as close as possible towards its center of mass. Given enough mass to overcome the strength of the material, the natural outcome is a sphere. The larger the object, the less deviations from a perfect sphere it will have.<p><hr /></p></p></blockquote><br />You do know there is a bigger question here? I'll give you a day to guess. <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[derekmcd]

No clue what you are getting at. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[alokmohan]

Why ?It is your name.

 

[why06]

Why? [yes that is my name]<br /><br />Is gravity uniform. Why is it 3 dimensional. I know this has hardly anything to do with th original question, but it helps to think about. Why exactly does gravity have to behave three dimensionally? <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[yevaud]

Why wouldn't it? Space is three-dimensional, and no axis is preferred to another. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[why06]

Exactly. So gravity must be caused by something 3-dimensional. <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[yevaud]

Er, no. That's not how physics works. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[why06]

Than explain it.... Im getting to a point here believe it or not. <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[yevaud]

That's deep physics. Best explanation: if you took a vast number of different physical theories and tried to model them, most wouldn't work. Gravity would be too strong, weak nuclear force too weak, whatever.<br /><br />Our universe seems to be optimal for it to exist and function, unlike all other possibilities. This included forces like gravity operating, in our continua, in three dimensions.<br /><br />That answer isn't going to satisfy you, but you've asked a question that can't really be answered, except to say, "that's what seems to have worked out." <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[derekmcd]

Our current knowledge does not allow us to observe things beyond 3 dimensions. The 4 fundemental forces we are aware of work quite well with our 3d universe. CERN might unravel some interesting things, but until that happens, there is a very solid foundation upon which scientists base their observations on. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[why06]

So if we can only feel gravity in three demensions is it possible that the reason gravity is weaker in certain aspects to other forces is because we do not exist in the same number of demensions that gravity affects. <br /><br />This goes into string theory. <br /><br />Now suppose gravity was not able to exhibited in higher dimensions would planets still be spherical. Or suppose gravity favors one universal direction more than another. But gravity is a force that is enforced equally in all directions. <br /><br />Like you said. "Our universe seems to be optimal for it to exist and function" We maybe one in a million or by astronomical standards One in billions... <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>